Shell

Routine maintenance requires a generic execution shell, but the CentOS 6 version is different from the 7 version of the command, and needs to be judged by the program itself, as follows:1. View cat/etc/centos-release[Email protected]/0 #

1.if judgment① simple judgment, if the condition is met, return OK#!/bin/basha=5if [$a-gt 3]then echo "OK" fi[[email protected] test_shell]#./test.shok② two conditions, you can use elif and else#!/bin/basha=5if [$a-lt 3]then echo "Common symbols in

Crontab can execute a shell script and execute a series of Linux commands at a specified timeExample: Server administrator regularly backs up database data, logs, etc.DetailedCommon commands:Crontab–e //Modify the crontab file, if the file does

CommonCtrl+r: Quick Search History Command (Retrieve)Ctrl+u: Delete entire command line text character (Unity)Ctrl+s: Pausing a Running program (STOP)Ctrl+q: Exit Pause (quit)CTRL + Z: Enables tasks that are running in the terminal, running in the

Processing of strings1. Interception of stringsMethod one, using the ${} expressionFormat: ${var: Start position: Length}Phone= "13788768897" # echo ${#Phone} 11 When you use ${} to intercept a string, the

1. If Judgment statement:Integer judgment:-eq equals-lt less than-gt greater than-le less than equals-ge greater than or equal to-ne not equal tostring judgment:-Z is null-n NOT NULL = equals! = is not equal to \> greater than \Logical judgment:-A

1. Variable assignment:NAME=LBG equals sign cannot have spaces name= "Lebron James" variable values have spaces in double quotes Echo ${name} with ${} More insurance shopt-s-O Nou Nset setting "Declare and use first"2. Cancel the variable:unset

First, IntroductionIt is an executable file. Design executable statements in advance to accomplish specific tasks1.1 Common script typesBash ShellPython/perl/rubyjsp/php/asp/cgiJavascriptThe biggest advantage of 1.2 shell languageCan be fully

Topic One: Summation exercise:#!/bin/bashfunction Sumarray {Local sum=0Local arrayArray= (echo "[email protected]")For value in ${array[]}Dosum=$[$sum + $value]DoneEcho $sum}Wang= (1 2 3 4 5)echo "Initial data is: ${wang[]}"Kai=echo ${wang[*]}result=

The SED stream editor is also a command in Linux that is often used in the shell to modify the contents of a file in a non-interactive way. The SED handles the text in rows, that is, one row at a time.The basic format of the SED command is:sed

The following is a syntax format for input and output redirection Two overview Output input redirectionGreater than sign >: Indicates output redirection (overwrites the original file)Less than Double greater than sign >>: (indicates output

A goal is a dream with a deadline. Much effort, Much prosperity.Why Encrypt shell scripts? Of course it's for security!Maybe the script involves a password or something, and it needs to be encrypted.I. Download and install the SHC toolTo protect

The execution name of this program$n the nth parameter value of this program, n=1..9$* all parameters of this program, this option can have more than 9 parameters.$# the number of parameters for this program$$ the PID of this program (the current

The issue cannot be removed after using HBase shell entry in Xshell:In the HBase shell, the wrong input instructions can not be deleted using backspace and delete, the use of the people know that this is a lot of pits, there is much distress!OK,

#!/bin/bash#第一次运行创建记录文件-f 1.txt || touch 1.txtwhile :do #查看日志中登陆失败的ip次数超过10次的用户ip fip=`awk ‘/Failed/{ip[$11]++;}END{for (i in ip){if (ip[i]>10){print i}}}‘ /var/log/secure` #循环取出登陆失败超过十次的ip进行处理 for i in $fip do #查看处理记录文件如果该ip没有存在处理记录中说明是没有处理过该ip

Note Using expr:The operator and the number used for the calculation have at least one space around it, otherwise the errorWhen using multiplication sign, a backslash must be used to mask its specific meaning.An enterprise-class case study of

#!/bin/bash#from为压缩包批次所在目录#basetarpath to count the total length of time per batchFrom=$1Basetarpath=$2suffix= "Tgz"Todir= $basetarpathoutdir= $basetarpath/home/iflytek/outif [!-d? $from]; ThenExitFiif [!-D $basetarpath];thenMkdir-p

0x00 Preface Scanner Scan to a website exists directory browsing, so there is this article ...Knowledge Point Popular Science:1. Directory browsing Directory browsing in my personal view is a significant vulnerability, the

Conditional test Syntax:Syntax 1:test This is the method of conditional test expressions with the test command.Syntax 2:[]: This is the way to test an expression with a single parenthesis, as with the use of the test command, the recommendedSyntax 3

There are two types of data in the shell: one is a numeric type, the other is a string type , and although the shell itself is a weak type, it can be so distinguished.If we need to store multiple values in a variable in the shell, we need a more